1. Field of the Invention
This invention relates to a method and apparatus for image reading, and more particularly to a method and apparatus for image reading in which read/write operations are executed through a plurality of read/write accesses relative to an image data memory.
2. Discussion of the Background
Image reading apparatus have been developed, such as scanners as an example, having an image memory for storing image data obtained through an operation for reading an original image. The image memory for this purpose has been generally composed of a plurality of DRAMs (dynamic random access memories) and/or SRAMs (static random access memories).
One example of various control mechanisms, used in a background image reading apparatus, for controlling such an image memory is disclosed in Japanese Patent Publication No. 6-1448 (1994), which converts serial image data into a parallel form so as to efficiently handle an input and output of a great amount of image data relative even to DRAMs, which DRAMs are not high-speed-processing chips.
In the above-described image reading apparatus, the image memory can be accessed only when the image data read from an original image is written thereto and the stored image data of the original image is read therefrom. However, other than the above-mentioned read and write operations, the image reading apparatus does not allow a data control unit or processing mechanism thereof such as a CPU (central processing unit) to access the image memory for various purposes including for examining correctness of the image data, for changing a part or a whole of the image data, and so forth.
Therefore, at present, there is no image reading apparatus which is capable of allowing a memory that stores image data to be accessed by a plurality of data control units.
Accordingly, an object of the present invention is to provide a novel image reading apparatus which is capable of allowing a memory that stores image data to be accessed by a plurality of data control units.
Another object of the present invention is to provide a novel method for an image reading apparatus to allow a memory that stores image data to be accessed by a plurality of data control units.
A further object of the present invention is to provide a novel memory control apparatus which is capable of allowing a memory that stores image data to be accessed by a plurality of data control units.
Still another object of the present invention is to provide a novel method for a memory control apparatus to allow a memory that stores image data to be accessed by a plurality of data control units.
The present invention achieves the above and other objects by implementing a structure and method with which different data control units, such as, as examples only, a scanner control unit and a central processing unit (CPU), can both access a memory. Such accesses can also be performed simultaneously.
Other objects, features, and advantages of the present invention will become apparent from the following detailed description when read in conjunction with the accompanying drawings.